RFC 1570 (rfc1570) - Page 2 of 18

PPP LCP Extensions

RFC 1570                   PPP LCP extensions               January 1994


         This feature is defined as a separate LCP Code, rather than a
         Configuration-Option, so that the peer need not include it with
         other items in configuration packet exchanges, and handle
         "corrected" values or "rejection", since its generation is both
         rare and in one direction.  It is recommended that
         Identification packets be sent whenever a Configure-Reject is
         sent or received, as a final message when negotiation fails to
         converge, and when LCP reaches the Opened state.

   A summary of the Identification packet format is shown below.  The
   fields are transmitted from left to right.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Code      |  Identifier   |            Length             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Magic-Number                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Message ...
   +-+-+-+-+-+-+-+-+


   Code

      12 for Identification

   Identifier

      The Identifier field MUST be changed for each Identification sent.

   Length

      >= 8

   Magic-Number

      The Magic-Number field is four octets and aids in detecting links
      which are in the looped-back condition.  Until the Magic-Number
      Configuration Option has been successfully negotiated, the Magic-
      Number MUST be transmitted as zero.  See the Magic-Number
      Configuration Option for further explanation.

   Message

      The Message field is zero or more octets, and its contents are
      implementation dependent.  It is intended to be human readable,
      and MUST NOT affect operation of the protocol.  It is recommended



Simpson